Imitation leather finish



atented July 26, 1938 UNITED STATES PATENT OFFICE IMITATION LEATHERFINISH No Drawing. Application May 7, 1936,

Serial No. 78,487

1 Claim.

This invention relates to a baked enamel finish on paper, rayon andother flexible supporting surfaces.

It is the object of my invention to provide a baked enamel finish thathas the characteristics upon drying of forming an irregular surface,imitating the appearance of leather.

It is my particular object to provide such a finish that when it is dry,its surface will be hard and non-adherent, just as is the case withleather, and will be as flexible as leather.

It is my object for this purpose to provide a finish the flexibility ofwhich is in proportion to and comparable with the supporting surface. Ihave found that by controlling the flexibility of the coating so as tobe in harmony with the flexibility of the supporting surface that I amenabled to get a resulting unitary composite product in which there willbe a permanent bond without cracking, flaking or the like between theenamel surface material and the supporting medium.

It is a further object to provide a finish of this desired plasticitywhich can be applied in any manner as by spray, roll coating, immersionand the like, and which can be dried preferably at room temperatures. Byproviding a finish which can be applied and brought to its finished hardstate at temperatures below that which would be destructive to thesupporting medium, it is possible to provide an enamel finish directlyupon paper, rayon, sheet rubber, artificial leather and other similarmaterials and the resulting finish can not only be brought to its finalhard, dry, smooth and flexible condition, but at a temperature that issatisfactory for the material in question which supports it.

It is my further object to provide an enamel finish which completely andof itself, when dry, assumes the irregular structure that ischaracteristic of an imitation leather. This irregularity extendsthroughout the body of the coating and not merely on the surface of it.By adjusting the plasticity of this coating this structural irregularityof the coating can take place upon drying without wrinkling thesupporting paper, rayon or other materials which are in themselvesflexible. It is further possible with my coating to coat delicatematerials so as to present the imitation leather finish on one side,without the material so coating the medium coming through the medium andshowing on the other side. It is therefore possible to print orotherwise use the back of this imitation leather finish, compositeproduct.

The principle of my invention is also applicable to other imitationleather finishes of my invention, where the baking temperature is higherthan that of room temperature. For instance, I have found that with theimitation leather finish of this invention, having this high plasticity,that I am able to coat paper and carry the temperature to 225 degrees F.for a period sufiicient to bring about the drying and irregular surfaceof the imitation leather finish without injuring the paper.

It will be understood that the proportions of the plasticizer that Ihave employed to bring about this novel result are very much greaterthan any heretofore ever contemplated in connection with lacquers,enamels and varnishes. I have found that by adding high boiling lacquerplasticizers in relatively large proportions and adjusting theproportions so as to bring about the same degree of flexibility in theimitation leather finish as in the paper or other medium being coated, Iam enabled to get the novel result of this invention.

It is my further object to provide for the application of this sameprinciple in imitation leather finishes that are baked, as on metal,such as metal foil or metal sheets at the higher temperatures of from300 to 400 degrees F. approximately.

In order to accomplish the several objects of this invention, I preparea varnish hereinafter described in Varnish I, a varnish described inVarnish II, and then combine the two varnishes as indicated in VarnishIII, to which I add a sufiicient amount of plasticizer preferably a highboiling lacquer plasticizer in order to impart the proper degree offlexibility depending upon the material to which the imitation leatherfinish is to be applied. For instance, in the case of book paper I havefound that by adding to ten gallons of Varnish III from one-fourthgallon to one gallon of high boiling lacquer plasticizer I am enabled toget the desired result. Amongst the plasticizers that can besuccessfully used in this connection are the following:

Diamyl phthalate, Tricresylphosphate, Triphenylphosphate,

Dibutyl phthalate,

Diethyl phthalate,

Phenyl stearate,

Monophenyl diphosphate, and Diphenyl phthalate.

Other plasticizers may be employed but I mention the foregoing as asufficient number of typical illustrations to make it possible foranyone skilled in this art to practice this invention. When I refer inthis specification and claim to a plasticizer, it will be understoodthat I comprehend within that term any one of these materials, orcombinations thereof, or an unmentioned equivalent thereof.

Varnish I A typical formula is the following:

Pounds Amberol 13/5 1 Lt 6'7 Litharge 3%; Manganese linoleate, solid 8Cobalt linoleate, solid 2 Gallons China-wood oil 20 Linseed oil 2% Heavypetroleum naphtha 14 Light petroleum naphtha 14-.

Amberol is a phenol, formaldehyde, synthetic resin. It is made asfollows: To one hundred parts of phenol aldehyde resin difficultlyfusible and only partly soluble in benzol and other solvents andproduced, for instance, by heating 108 parts of cresol with 60 to '75parts of formaldehyde (30% by weight) and distilling off the Water andthe uncombined cresol, are added gradually to 800 parts of meltedcolophony. The whole mixture is then heated in an autoclave until aresin is produced which is clear in the cold, homogeneous and free fromsmell of phenol. The volatile substances are then removed while stirringand parts of glycerol of 28 degrees B. are added in small quantitieswhereupon the mixture is heated to 250 degrees C. and kept at thistemperature for several hours while being stirred carefully. A typicalformula for amberol is shown in United States Patent No. 1,623,901.

In order to prepare this varnish, we first take 20 gallons of China-woodoil or tung oil and 2 gallons refined linseed oil. These oils are mixedand heated at a normal rate to 480 degrees F. They are then pulled fromthe fire. These oils may undergo an automatic rise in temperaturethereafter beyond 480 degrees F., but this is unnecessary and too greata rise should be avoided.

When the temperature of these oils has started to drop reachingapproximately 475 degrees R; we add 3%.; pounds of litharge, stirringuntil the litharge is taken up by the oil. The temperature of this batchis then run back and forth between 460 degrees and 470 degrees, beingheld within this range for approximately 30 minutes and in some cases alittle longer until suificient body has been imparted to the oil andlitharge..

Thereafter we add 8 /2 pounds of manganese solid linoleate and 2 poundsof cobalt solid linoleate. These soluble driers melt into the batch.

We then add 67 pounds of synthetic resin solid, known to the trade asAmberol B/S 1 Light. This is melted at a low heat. Then the temperatureis carried back to approximately 425 degrees F.

We then thin the batch at once with 14 gallons each of heavy and lightpetroleum naphtha.

The resulting compound may be used by itself or in combination with theproduct of the formula hereinafter recited.

Thereafter we prepare Varnish II.

Varnish II This formula is as follows:

' Pounds South Sea gum (Batu) 67 Litharge 3 Manganese linoleate 8 Cobaltlinoleate 2 Gallons China-wood oil 20 Linseed oil 2%, Heavy petroleumnaphtha 20 Light petroleum naphtha 20 The cooking is carried out in thismanner. Sixty-seven pounds of South Sea gum, also known as Batu gum, arerun in the ordinary approved fashion customary in varnish making. Then20 gallons of China-wood oil and 2% gallons of refined linseed oil aremixed and heated'slowly until they reach 300 or 350 degrees F., thenthey are added slowly to the gum when the latter has been well run.

The mixture is then carried to a temperature of 460 to 470 degrees F.and held within this range, in order to impart body to the mixture, forabout 30 minutes or a little longer.

We then stir into the batch 3 /2 pounds of litharge until it is taken upand fully incorporated in the batch. The 8 pounds of manganese solidlinoleate and 2 pounds of cobalt solid linoleate In order to make thecompound of this inven- 3 tion, either one of the above varnishes orboth are combined with raw tung (China-wood) oil and a drier. A thinnercan be added optionally. The proportion of Varnish I with respect toVarnish II may be two to one, or vary therebetween, or Varnish II withrespect to Varnish I may be two to one, or vary therebetween. In eitherevent, the China-wood oil will vary in number of parts fromapproximately 5 to 25 parts. The drier will vary from approximatey 5 to25 parts, and the thinner will vary from 1 to 10 parts, depending uponthe viscosity desired.

Varnish III A typical example of a satisfactory compound for thepractice of this invention is the following:

Parts Varnish I 81 Varnish II 40 Raw tung (China-wood) oil 9 Drier 9Petroleum naptha 5.10

Varnish IV To ten gallons of Varnish III I now add from gallon to 1gallon of any one of the following Amongst such plasticizers or theirequivalents.

high boiling lacquer plasticizers that I have employed are thefollowing:

Diamyl phthalate, Tricresylphosphate, Triphenylphosphate,

Dibutyl phthalate,

Diethyl phthalate,

Phenyl stearate.

Monophenyl diphosphate, and Diphenyl phthalate.

It will be understood that under some circumstances, with extremelyflexible supporting media, it may be necessary to increase theproportion of the plasticizer, but generally the amount of plasticizerto be added varies from 2 to 10% by volume of the imitation leatherfinish material such as that shown in Varnish III, but my inventionrests in having a relatively high proportion of plasticizer in animitation leather finish coating and adjusting the quantity so as togive a plastic finish of the same degree of flexibility as thesupporting medium, susceptible of application to other formulas ofimitation leather finishes.

I further have found that by adjusting the drying rate I am able tocontrol the velocity of the surface drying and the drying through thefilm of imitation leather finish, so as not to wrinkle the paper orother material upon which the finish is being applied, and at the sametime, preserve the flexibility of the coating.

For instance, when the compound of this invention is applied it mustfirst flow out evenly on the surface treated and then the drying mustbegin almost at once on the surface of the wet compound by the formationof microscopic wrinkles. This initial wrinkling then proceeds throughthe whole thickness of the film as the complete drying proceeds.

The preferred drier that I have found to best serve this purposecomprises linoleate of lead, linoleate of cobalt, and linoleate ofmanganese. The cobalt and manganese, particularly the cobalt, acceleratethe surface drying, as described above, while the lead and manganese areutilized for completing the drying completely through the film. Thiscombination of cobalt and manganese supplies quick initial surfacedrying necessary, while the lead and the manganese supply the necessarycatalytic action for the drying through the film.

Drier Example One of the preferred formulas which we have used is asfollows:

385 pounds of linoleate of lead, 889 pounds of linoleate of cobalt,

14 pounds of linoleate of manganese.

These are melted at as low heat as possible, and when entirely fluid themass is thinned with 1202 gallons of turpentine, either gum spirits orwood spirits, or some slowly evaporating coal tar fraction, such asxylene. It will be understood that the proportions of these elements ofthe drier can be varied according to the result desired. By adjustingthese proportions the velocity of the surface drying and dryingthroughout the film can be regulated.

By utilizing the following formulas I find I am able to take my dryingtemperature of an imitation leather finish on paper up to 225 degrees F.without injuring the paper.

Varnish V A typical formula is the following:

Pounds Amberol B/S 1 Lt 67 Litharge 3 A; Manganese linoleate. solid 8 /2Cobalt linoleate, solid 2 Gallons China-wood oil 20 Linseed oil 2% Heavypetroleum naphtha 14 Light petroleum naphtha 14 A suitable substance tobe used as Amberol, in the above formula, is disclosed in U. S. LettersPatent No. 1,623,901, dated April 5, 1927.

In order to prepare this varnish, I first take 20 gallons of China-woodoil and 2%; gallons refined linseed oil. These oils are mixed and heatedat a normal rate to 480 degrees F. They are then pulled from the fire.These oils may undergo an automatic rise in temperature thereafterbeyond 480 degrees F. but this is unnecessary and too great a riseshould be avoided.

When the temperature of these oils has started to drop reachingapproximately 475 degrees F., I add 3 pounds of litharge, stirring untilthe litharge is taken up by the oil. The temperature of this batch isthen run back and forth between 460 and 470 degrees F., being heldwithin this range for approximately 30 minutes and in some cases alittle longer until sufficient body has been imparted to the oil andlitharge.

Thereafter I add 8 pounds of manganese solid linoleate and 2 pounds ofcobalt solid linoleate. These soluble driers melt into the batch.

I then add 67 pounds of synthetic resin solid, known to the trade asAmberol 3/5 1 Light." This is melted at a low heat. Then the temperatureis carried back to approximately 425 degrees F.

I then reduce the batch at once with 14 gallons each of heavy and lightpetroleum naphtha.

There may be added the plasticizers in proportions indicated heretofore.

Or, the addition of the plasticizer may be deferred until the followingvarnish, set forth in Varnish VI is added, whereupon the plasticizer canbe added to the combined varnishes of V and VI.

In both cases of Varnish V or Varnishes V and VI, the imitation leatherfinish is applied to the paper or other media, and the temperature iscarried up to 225 degrees F. for a period of approximately one-half hourto three hours. By regulating the proportion of the drier, as heretoforeindicated, and the proportion of the plasticizer, it is possible tosecure an irregular surfaced and an irregular body of an imitationleather finish, without wrinkling the paper and of the same flexibilityor even greater flexibility than that of the paper and without the heatinjuring the paper.

The cooking is carried out in this manner. Sixty-seven pounds of SouthSea gum are run in the ordinary approved fashion customary in varnishmaking. Then 20 gallons of China-wood oil and 2% gallons of refinedlinseed oil are mixed and heated slowly until they reach 300 or 350degrees F., then they are added slowly to the gum when the latter hasbeen well run.

The mixture is then carried to a temperature of 460 to 4'70 degrees F.and held within this range in order to impart body to the mixture forabout 30 minutes or a little longer.

I then stir into the batch 3% pounds of litharge until it is taken upand fully incorporated in the batch. The 8 pounds of manganese solidlinoleate and 2 pounds of cobalt solid linoleate are allowed to melt inthe batch.

I then reduce at once with 20 gallons each of heavy and light petroleumnaphtha.

Turpentine may be substituted for the naphtha. Either the natural gum ora synthetic product as Amberol may be employed. When the natural productis used the result is a liquid of greater viscosity.

The fundamental basis is the combination of a guru and a low cookedChina-wood oil. The litharge has the function of drying the compoundthrough and through while the manganese and cobalt linoleates actprimarily as surface or finish driers. The naphthas act as thinners. Thelinseed oil is an anti-polymerizing agent.

At this point I now preferably add to the co1nbination of varnishes Vand VI in the approximate proportions of one part each of the proportionof the high boiling lacquer plasticizers heretofore enumerated of fromgallon to one gallon of the plasticizer to each ten gallons of thecombined Varnishes V and VI. This combination can be applied to paperand the like and heated to a temperature of 225 degrees F. forapproximately one-half hour to three hours, depending on the ultimateuse. The temperature of baking can be carried to approximately 225degrees F. and held at that temperature for about 3 hours, but,

of course, the time of baking, the nature of the atmosphere in whichbaked, and the movement of that atmosphere will depend upon thesupporting material and the coating.

For the application of a smooth enamel to paper, I take an enamel,preferably one made of a long oil spar varnish, and the necessarypigments to give the desired color.

To ten parts of this enamel I add from onefourth to one gallon of highboiling lacquer plasticizer and I am enabled to get the desired results.

Such an enamel can consist, for example, of 80 pounds of carbon blackand 505 gallons of spar varnish. To ten gallons of the above varnish Iadd one-half gallon plasticizer.

Different colors may be imparted to the leather finish by addingultra-marine blues, chrome yellows and greens, chrome oxide greens, andtoluidine and lithol reds, etc.

It will be understood that I desire to comprehend within my inventionsuch modifications as may be necessary to adapt it to varying conditionsand uses.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent, is:

An improved imitation leather enamel composition adapted for coatingrelatively thin flexible materials and drying to a high flexible wrinklefinish film at forced drm'ng temperatures approximating 225 degreesFahrenheit, consisting by volume of approximately eighty-one parts ofsynthetic resin Varnish I; approximately forty and one-half parts ofVarnish II; approximately nine parts of raw China-wood oil;approximately nine parts of a drier composed of a mixture of lead,cobalt, and manganese linoleate compounds dissolved in turpentine; fiveto ten parts petroleum naphtha thinner; color ground in spar varnish;and a high boiling point plasticizer in the amount approximating tenpercent by volume of the enamel composition.

HARVEY G. KITTREDGE.

